Blackholes
In 2015, scientists first detected gravitational waves. These ripples in space-time were caused by two black holes colliding and shaking the Universe.
Gravitational Lensing
Space is not flat. It is 3D, and we say that everything in it is held together on an imaginary surface we call spacetime. The idea of spacetime was put forward in Einstein's theory of relativity.
- How does Gravitational Lensing happen?
Lensing happens when light from directly behind a massive object, from our line of sight, can be bent around it. We call this gravitational lensing, and it is a way to see an example of the theory of relativity.
Gravitational Waves
Gravitational waves are tiny, invisible ripples in space. They travel for huge distances at the speed of light. The waves squeeze and stretch any objects they pass, but only by a tiny amount.
- Evidence for Gravitational Waves
On 14th September 2015, scientists announced they had the first evidence for gravitational waves. This was nearly 100 years after Einstein published his work.
Relativity
Gravity is the force we are most familiar with in everyday life. It has been studied for longer than the other forces of nature. However, it is also the least well understood.
- Law of Universal Gravitation
Newton had correctly explained that every object in the Universe has a force which can be felt by every other object as a ‘pull’. We call it an ‘attractive’ force because it attracts objects towards each other.
The strength of this force is linked to the mass of the object. The more massive the object, the stronger the force. Newton also found that the force is linked to the distance between the objects. The further the distance, the weaker the force.
Gravity
Gravity is the name of the force that pulls objects together. It is a non-contact force. This means it acts on objects that are not touching each other.
- Gravitational Field Strength
All objects with mass have a gravitational field. We measure the gravitational field strength (g) in N/kg. The more mass an object has, the greater its gravitational field strength will be.
On Earth, g = 9.8 N/kg.
- Weight
Weight is the force acting on an object due to gravity. It is measured in Newtons (N). You can calculate weight using this equation.
Weight = Mass x Gravitational Field Strength
Arthur Eddington
Occupation
Astronomer, Physicist, Mathematician
Year Born
1882
Research Areas
Nuclear fusion processes inside stars, General Relativity
- Early Life
Arthur was born in Cumbria, UK before moving to Weston-super-Mare as a child. He was not from a wealthy family. But he did so well at school that he got a scholarship to go to Owen's College, Manchester.
He graduated with a physics degree in 1902. Arthur was then offered a position at Trinity College, Cambridge where he completed his master’s degree. He worked at the Royal Observatory in Greenwich, London, before returning to Cambridge five years later.
How Do Satellites Stay In Orbit?
A satellite is an object which orbits another. An orbit is the curved path that an object in space takes around another object.
Explore Gravity
Use our simulator to investigate the effect of gravity on other worlds. Then use your measurements and a bit of maths to calculate the strength of gravity in each location across the Solar System!
Kepler's Laws: Find the Mass of the Sun
Many years ago, a mathematician named Johannes Kepler created a set of rules explaining planets' movement in our Solar System.